Quick-change chucks

ABSTRACT

A quick-change chuck with a hollow shank, a guide sleeve surrounding the shank, a tool-holding socket removably inserted into the shank and adapted to be adjusted to different positions in the axial direction of the shank by an adjusting nut on the end of the socket which is releasably connected in the adjusted position to the shank by locking balls which are guided in transverse bores in a reduced neck portion of the guide sleeve and are adapted to be moved into and out of an annular groove in the adjusting unit by a spring-biased control sleeve. For locking the guide sleeve and thus also the adjusting nut and the tool socket to the shank, the guide sleeve is provided with a peripherally extending slot through which a setscrew passes which is screwed into the shank. The axis of this slot is slightly inclined relative to a plane extending vertically to the axis of the guide sleeve so that, when the sleeve is turned relative to the setscrew in the slot, the sleeve is retracted on the shank until its neck portion abuts tightly against the front end of the shank.

United States Patent 51 June 27, 1972 Fauth [54] QUICK-CHANGE CHUCKS[72] Inventor: Otto F auth, Nellingen, Germany [73] Assignee: Otto Bilz,Werkzeugfabrik, Vogelsangstr.,

Nellingen, Germany [22] Filed: May 18, 1970 [21] Appl. No.: 38,080

[51] Int. Cl ..B23b 31/04 [58] Field ofSearch ..279/1 B, 82, 81,83, 75

[56] References Cited UNITED STATES PATENTS 3,473,815 10/1969 Bilz ..L..279/82 2,960,343 11/1960 Elledge.... ..279/81 3,070,380 12/1962l-lolmberg... ..279/75 X 3,219,355 11/1965 Fujinuma ..279/75 PrimaryExaminer-Andrew R. .luhasz Assistant Examiner-Z. R. BilinskyAlt0rneyCraig, Antonelli and Hill [57] ABSTRACT A quick-change chuckwith a hollow shank, a guide sleeve surrounding the shank, atool-holding socket removably inserted into the shank and adapted to beadjusted to different positions in the axial direction of the shank byan adjusting nut on the end of the socket which is releasably connectedin the adjusted position to the shank by locking balls which are guidedin transverse bores in a reduced neck portion of the guide sleeve andare adapted to be moved into and out of an annular groove in theadjusting unit by a spring-biased control sleeve. For locking the guidesleeve and thus also the adjusting nut and the tool socket to the shank,the guide sleeve is provided with a peripherally extending slot throughwhich a setscrew passes which is screwed into the shank. The axis ofthis slot is slightly inclined relative to a plane extending verticallyto the axis of the guide sleeve so that, when the sleeve is turnedrelative to the setscrew in the slot, the sleeve is retracted on theshank until its neck portion abuts tightly against the front end of theshank.

4 Claims, 2 Drawing Figures QUICK-CHANGE CHUCKS The present inventionrelates to improvements in a quickchange chuck of the type as disclosedin my US. Pat. No. 3,473,815, which comprises a hollow cylindricalshank, a tool socket which is axially slidable within the shank andadapted to receive a tool, an adjusting nut which is adapted to bescrewed upon the front end of the socket for shifting the socket in itsaxial direction relative to the shank. This adjusting nut has acylindrical neck portion and a peripheral groove within this neckportion which groove is provided with two outwardly inclined flanks. Bythe action of a spring-biased control sleeve, which is axially movableon the shank, a plurality of locking balls are movable substantiallyradially into and out of the groove, while a guide sleeve which isfitted over the shank and, in turn, surrounded by thecontrol sleeve hason its front end an annular neck of a smaller diameter. This neck whichforms an inner shoulder which is adapted to abut against the front endof the shank is provided with transverse bores for guiding the lockingballs. Near its rear end the guide sleeve is locked to the shank bymeans of a setscrew which is inserted through a transverse bore in thissleeve and screwed into a tapped bore in the shank.

it is an object of the present invention to improve the quickchangechuck as disclosed in my previous patent and as briefly described aboveby designing the transverse bore in the guide sleeve through which thesetscrew is inserted so as to form a slot-shaped hole which extends inthe peripheral direction of the sleeve and the longitudinal axis ofwhich is slightly inclined to a plane extending vertically to thelongitudinal axis of the sleeve. If desired, it is also possible toprovide two or more similar inclined slot-shaped holeswhich are slightlyoffset to each other in the longitudinal direction of the sleeve andinto one or the other of which the setscrew may be inserted. Theaperture in the outer control sleeve through which the setscrew isaccessible is sufficiently enlarged to permit the guide sleeve to beturned, and if several slot-shaped holes are pro vided in the guidesleeve, the control sleeve may be provided with several enlargedapertures which are likewise longitudinally offset relative to eachother in accordance with the slot-shaped holes in the guide sleeve.

If according to my previous patent the smooth circular bore in the guidesleeve was made of the same diameter as the setscrew, the occurrence ofa slight tolerance from the prescribed positions of this bore and ofthethreaded bore in the shank either prevented the setscrew entirelyfrom being screwed into the shank or the shoulder on the neck of theguide sleeve from tightly abutting against the front end of the shankwith the result that the adjusting nut together with the tool socket wasmovable in the axial direction relative to the shank. This last resultalso occurred if, in order to compensate for such possible tolerances,the bore in the guide sleeve as made of a larger diameter than thesetscrew.

If in accordance with the present invention the guide sleeve is providedwith a slightly inclined, peripherally extending slot in place of acircular bore, the guide sleeve when being turned about its axisrelative to the setscrew will also be retracted longitudinally along theshank until the shoulder onthe neck of the guide sleeve will abuttightly against the surface of the front end of the shank. Thepresentinvention therefore permits the guide sleeve to be securelylocked to theshank even if the position of the threadedbore in the shank differsslightly from its prescribed position. This is of importance especiallyalso ina case in which the guide sleeve is to be mounted on a similar,already existing shank which is provided with a threaded bore for asetscrew in a position whichdiffers slightly from the position asrequired for mounting a guide sleeve thereon which is made in accordancewith the invention.

Since the inclination of the slot in the guide sleeve is very small, aself-locking friction occurs between the setscrew and one wall of theslot when the shoulder on the guidesleeve abuts against the end of theshank. Thus, there areno additional means required for preventing theguide sleeve from turning back and shifting to a position in which theneck of the guide sleeve does not tightly abut against the front-end ofthe shank.

The feature of the invention will become more clearly apparent from thefollowing detailed description thereof which is to be read withreference to the accompanying drawings, in which FIG. 1 shows alongitudinal section of a quick-change chuck according to the invention;while FIG. 2 shows a plan view of the lower part of the chuck accordingto FIG. 1.

The quick-change chuck according to the invention is of the same generalconstruction as the chuck which has been described in detail in my priorpatent as above referred to and which comprises a hollow cylindricalshank or housing 1 into which an adjustable tool-holding socket 2 may beinserted upon the threaded front end of which an adjusting nut 4 isscrewed. A guide or locking sleeve 22 which is slipped over the shank 1has a front end in the form of a neck portion 26 of a smaller diameterwhich engages upon the end surface 21 of the shank 1 and is providedwith radial bores in which locking balls 6 are radially slidable whichare adapted to engage into an annular groove in the adjusting nut 4 whena guide sleeve 22 is retracted by a spring so that a tapered surface onan inwardly projecting annular flange on the front end of this guidesleeve which surrounds the neck portion 26 of sleeve 22 presses theballs into the annular groove of the adjusting nut. When the controlsleeve is shifted forwardly along the guide sleeve against the action ofthe spring, the locking balls 6 may move radially toward the outside andout of the peripheral groove in the adjusting nut 4 so that the toolsocket 2 with the adjusting nut 4 thereon may then be withdrawn from theshank 1.

Near its rear end, guide sleeve 22 is locked to the shank l by asetscrew17 which is inserted through a transverse aperture 19 in guidesleeve 22 and screwed into the shank 1. If, as shown in the drawings,the control sleeve 3 projects toward the rear beyond thesetscrew 17,this sleeve 3 is provided with an aperture 18 through which the setscrew18 may be inserted and turned by a screw driver.

While according to my prior patent the transverse aperture 19 in guidesleeve 22 through which the setscrew 17 is inserted consists of a smoothcircular bore, the present invention provides that, for locking theguidesleeve 22 to the shank 1 so as to prevent any movement of these twoelements relative to each other in the axial direction, the aperture 19in guide sleeve 22 is provided in the form of a slot-shaped hole whichextends in the peripheral direction of sleeve 22 and the longitudinalaxis of which is slightly inclined to a plane which extends verticallyto the longitudinal axis of this sleeve. lf guide sleeve 22 is turned inone direction about its axis relative to shank l, the inclination of thewalls of the slot-shaped hole 19 causes the guide sleeve 22 to beshifted slightly toward the rear so that its neck portion 26 will bepressed tightly against the front-end surface of shank 1. Since thisinclination of the walls of the slot-shaped hole 19 is very small, aself-locking friction will then occur between one side wall of this holeand the setscrew 17 which insures that guide sleeve 22 will remain inthe locked position in which the neck portion 26 abuts tightly againstthe end surface of shank 1.

If the positions of the threaded bores for the setscrew 17 of differentshanks l differ considerably from each other in the longitudinaldirection of the shanks, it is also possible to provide severalslot-shaped holes 19 at different positions of the periphery of eachguide sleeve 22. These holes 19 the walls or axes of which may beequally inclined should then be slightly offset relative to each otherin the axial direction of sleeve 22. Thus, if a secure locking actionbetween guide sleeve 22 and shank 1 cannot as yet be attained whensetscrew 17 is inserted through one inclined hole 19 and screwed intoshank l and into another inclined hole 19 and screwed again into thesame bore in shank 1. When guide sleeve 22 is then turned, the lockingeffect which could not be attained by means of the first inclined hole19 will now be attained by the second inclined hole 19.

If the control sleeve 3 is made of a length as shown in the drawings soas to project toward the rear beyond the setscrew 17, the slot-shapedhole 19 is made accessible for the purpose of inserting the setscrew andturning the guide sleeve 22 to its locking position by providing thecontrol sleeve 3 in a position substantially corresponding to theposition of the slot-shaped hole 19 in guide sleeve 22 with asufficiently large bore 18 or with an oblong hole similar to and atleast as wide as the hole 19. If several slot-shaped holes 19 areprovided in guide sleeve 22, the control sleeve 3 may either be turnedso that its large bore 18 or a sufficiently wide oblong hole overliesthe hole 19 or the control sleeve 3 may be provided with several boresor oblong holes in positions substantially corresponding to those of theholes 19 in guide sleeve 22.

Although my invention has been illustrated and described with referenceto the preferred embodiments thereof, I wish to have it understood thatit is in no way limited to the details of such embodiments but iscapable of numerous modifications within the scope of the appendedclaims.

Having thus fully disclosed my invention, what I claim is:

1. In a quick-change chuck comprising a cylindrical shank having atubular wall, a tool socket axially slidable within said shank andadapted to receive a tool, an adjusting nut adapted to be screwed uponthe font end of said socket for shifting said socket in its axialdirection relative to said shank, said nut having a crylindrical neckportion and a peripheral groove within said neck portion, a guide sleevesurrounding said shank and having on its front end an annular neck of asmaller diameter forming an inner shoulder adapted to abut against thefront end of said shank, and having a plurality of transverse borestherein, a plurality of locking balls movable substantially radiallywithin said transverse bores into and out of said peripheral groove, aspring-biased control sleeve surrounding and slidable axially along saidguide sleeve for guiding the radial motion of said balls,said shankhaving a tapped bore and said guide sleeve having a hole substantiallyin alignment with said tapped bore when said shoulder on said guidesleeve abuts against the front end of said shank, and a setscrewinserted into said hole and screwed into said tapped bore for lockingsaid guide sleeve to said shank, the improvement comprising means forensuring the abutment of said shoulder on said guide sleeve against saidshank so as to prevent movement therebetween consisting in providingsaid hole in the form of an elongated slot of a certain length extendingin the peripheral direction of said guide sleeve and having a widthsubstantially equal to the thickness of said setscrew and having alongitudinal axis slightly inclined relative to a plane extendingvertically to the axis of said guide sleeve.

2. A quick-change chuck as defined in claim 1, wherein said guide sleeveis provided with at least two of said inclined slots at different partsof the periphery of said guide sleeve and slightly offset relative toeach other in the longitudinal direction of said guide sleeve.

3. A quick-change chuck as defined in claim 1, wherein said controlsleeve extends beyond the rear end of said guide sleeve and has at leastone aperture therein having a sufficient size to permit said setscrew tobe inserted through said aperture into and through said slot and to bescrewed into said tapped bore in said shank and also to permit saidguide sleeve to be turned about its axis relative to said setscrew so asto shift said guide sleeve in its longitudinal direction until itsshoulder on said neck abuts tightly against said end surface of saidshank.

4. A quick-change chuck as defied in claim 3, in which the inclinationof said slot is so small that, when said guide sleeve has been turned sothat said shoulder abuts tightly against said end surface of said shank,a self-locking friction occurs between said setscrew aild gne side wa l]of said slot.

1. In a quick-change chuck comprising a cylindrical shank having atubular wall, a tool socket axially slidable within said shank andadapted to receive a tool, an adjusting nut adapted to be screwed uponthe font end of said socket for shifting said socket in its axialdirection relative to said shank, said nut having a crylindrical neckportion and a peripheral groove within said nEck portion, a guide sleevesurrounding said shank and having on its front end an annular neck of asmaller diameter forming an inner shoulder adapted to abut against thefront end of said shank, and having a plurality of transverse borestherein, a plurality of locking balls movable substantially radiallywithin said transverse bores into and out of said peripheral groove, aspring-biased control sleeve surrounding and slidable axially along saidguide sleeve for guiding the radial motion of said balls, said shankhaving a tapped bore and said guide sleeve having a hole substantiallyin alignment with said tapped bore when said shoulder on said guidesleeve abuts against the front end of said shank, and a setscrewinserted into said hole and screwed into said tapped bore for lockingsaid guide sleeve to said shank, the improvement comprising means forensuring the abutment of said shoulder on said guide sleeve against saidshank so as to prevent movement therebetween consisting in providingsaid hole in the form of an elongated slot of a certain length extendingin the peripheral direction of said guide sleeve and having a widthsubstantially equal to the thickness of said setscrew and having alongitudinal axis slightly inclined relative to a plane extendingvertically to the axis of said guide sleeve.
 2. A quick-change chuck asdefined in claim 1, wherein said guide sleeve is provided with at leasttwo of said inclined slots at different parts of the periphery of saidguide sleeve and slightly offset relative to each other in thelongitudinal direction of said guide sleeve.
 3. A quick-change chuck asdefined in claim 1, wherein said control sleeve extends beyond the rearend of said guide sleeve and has at least one aperture therein having asufficient size to permit said setscrew to be inserted through saidaperture into and through said slot and to be screwed into said tappedbore in said shank and also to permit said guide sleeve to be turnedabout its axis relative to said setscrew so as to shift said guidesleeve in its longitudinal direction until its shoulder on said neckabuts tightly against said end surface of said shank.
 4. A quick-changechuck as defied in claim 3, in which the inclination of said slot is sosmall that, when said guide sleeve has been turned so that said shoulderabuts tightly against said end surface of said shank, a self-lockingfriction occurs between said setscrew and one side wall of said slot.